This invention relates to an improved checking device that is used to test the pressure switches on the air brake manifolds of locomotives.
The air brake manifolds of locomotives are provided with a series of pressure sensitive switches that perform a variety of functions in connection with sensing the air pressure in the brake lines. For example, with locomotives having a lead or master unit and a remote or slave unit that is radio controlled in accordance with the operation of the master unit, the pressure switches assure that the braking of the remote unit conforms with that of the master unit. If the pressure switches are not adjusted correctly, the brakes will not work properly at either the master or remote position.
These pressure switches must be frequently checked to determine that they are operating properly. At present, testing of the switches requires removal of a cover plate so that an ohmmeter can be connected across the switch terminals to sense whether or not the switch is opening and closing properly. Also, the fitting for the air line leading to the switch must be disconnected and replaced by a male adapter. A main reservoir line is then tapped, and a hose equipped with a pressure gauge and pressure reducing valve is connected between the main reservoir line and the male adapter. The reducing valve is adjusted to the proper test pressure which is to be applied to the switch in order to ascertain whether or not it is opening and closing as intended. If adjustment of the switch is needed, a cover plate is removed from the front of pressure switch and an adjustment screw is turned in the appropriate direction. After the test, the ohmmeter must be disconnected and the cover plate replaced, and the male adapter must be removed and replaced by the fitting for the air line.
As can be easily appreicated, this present testing procedure is difficult, cumbersome, time consuming, and expensive, thus adding significantly to the maintenance costs of the locomotive equipment. The need to tap into the main reservoir line and connect the tap line with the added male adapter requires additional plumbing skills and supplies. Further aggravating the inconvenience and expense is the inaccessibility of the pressure switches, which are typically located within the locomotive on the air brake manifold.
It is the primary object of the present invention to provide an improved checking device for the pressure switches of locomotives in order to reduce the difficulty and labor costs associated with testing the switches.
Another object of the invention is to provide a checking device of the character described which presents, at a single accessible location, convenient connections for both the electrical and air pressure testing equipment. In accordance with the invention, each bank of switches has its own test panel that includes a pair of plug in type electrical receptacles for each switch, accompanied by a nearby quick connect coupling for the air test hose. Accordingly, an ohmmeter can be quickly and easily connected across the receptacles, and the test hose can be readily connected to and disconnected from the air line coupling, thereby eliminating the time, difficulty and expense involved in dismantling and reassembling the pressure switches as has been necessary in the past.
A further object of the invention is to provide, in a checking device of the character described, a quick connect coupling on the test panel which supplies pressure from the main air reservoir of the brake system. This feature of the invention is important in that the test hose can simply be connected at one end with the main reservoir coupling on the test panel and at the other end with the coupling for the pressure switch that is to be checked. This eliminates the cumbersome prior art technique of tapping into the main reservoir line and connecting the tap line successively to each pressure switch adapter.
An additional object of the invention is to provide a checking device of the character described which is simple and economical to construct and install, and which minimizes the amount of plumbing and electrical wiring.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.